The belt fastener apparatus disclosed herein will be described in conjunction with a hinged belt fastener such as shown in U.S. Pat. Nos. 3,742,557; 3,176,358 and 6,053,308. Features of the present invention may also be used with the typical plate kind of belt fasteners as shown in U.S. Pat. No. 3,141,346. The present invention is not limited to these particular belt fasteners identified herein as other belt fasteners may be used which have upper and lower plate portions secured to the top and bottom surfaces of a belt by fasteners.
In the hinged belt fastener, an upper and lower plate are joined by central U-shaped hinge or loop portions. These adjacent hinge portions are pivotally connected by a hinge pin to complete the belt splice between rows of individual hinge belt fasteners along each of the opposite belt ends.
Preferably, these upper and lower plates are secured tightly to and generally flush against the respective top and bottom sides of the conveyor belt by rivet fasteners. Typically, the rivets have an upper, preformed head which seats in a recess or depression in the top of a plate or fastener and the opposite end of the rivet is upset or flared to form a lower rivet head which then is seated in a recess or depression in the lower plate of the belt fastener.
In a widely use conventional belt fastener system now in the prior art, the U-shaped hinge portions of a row or strip of hinged belt fasteners are held in alignment along the belt end by a gauge pin on the belt fastening apparatus. More specifically, the gauge pin is located through openings in a series of upstanding guide members fixed to the anvil base and through the loop portions of the belt fasteners aligned and located on the tool. In this conventional tool, there are lower anvil plates with rivet head forming bushings raised above the surface of the lower anvil plate to upset the lower hollow ends of the rivets into the shape of rivet heads. Usually, the rivets are attached to the lower end thereof to a pointed pilot nail which is driven through the belt carcass, and then the pilot goes into the hollow rivet forming bushings for cooperation with the rivet head forming bushings to upset the thin, hollow cylindrical wall on the lower end of the rivet into the lower rivet head.
In some applications, the operator will individually align and drive the rivets one by one into the belt fasteners. Usually, a faster operation is obtained by using a guide block having a plurality of rivet receiving, through bores each of which is loaded with a rivet; and a common driver having a drive pin for each of the loaded rivets is driven to drive simultaneously the drive pins through the bores in the quick block and to drive the rivets through the upper and lower plate apertures and to form the lower rivet heads.
Prior to driving the strip of belt fasteners in the tool, the belt end was is inserted into the gap between the upper and lower plates until the belt end hit belt stops integrally formed on the belt fasteners. Then, the belt is clamped in this inserted position by turning a pair of L-shaped handles which have screw threads in the clamping bar and in the lower plate of the tool so that the clamping bar is pushed down toward the anvil plates located at the lower side of the belt end.
After belt insertion and clamping and loading of the rivets in the guide block, the common driver having the plurality of drive rods is hit with a large hammer or mallet to simultaneously drive the loaded pilot nails and rivets through the belt carcass and to bend down the upper plate of the belt fastener from an upwardly, inclined position to a horizontal position flat against the top side of the belt. The rivets are driven through the belt carcass to cause the hollow ends of the rivets to be upset by the raised bushings to form the lower heads on the rivets.
In some instances the belt clamp may not be effective in holding the belt securely fixed in the clamped position within the belt fasteners between the upper and lower plates thereof. Instead of using a belt clamp bar or the like, as described in U.S. Pat. No. 6,053,308, the belt fastener's upper or lower plates may be provided with integral projecting teeth which can be driven into the belt to secure the belt end and to hold it in position as the rivets are being driven through the belt and upset to form the lower rivet heads. Although the above described conventional tool operates quite successfully and has been employed in large numbers for a number of years, it has been found that the clamping bar is not as effective as desirable. In some instances, some operators dispense with the use of the clamping bar and merely tack or nail the belt to an underlying board to prevent outward movement of the belt end from its original location inserted fully between the upper and lower fastener plates during the hammering and the pounding of a succession of the belt fasteners in the strip. If the belt end withdraws or otherwise shifts from its fully inserted position, the rivet may be driven through the belt carcass at a location very close to the belt edge leaving insufficient belt material to resist tearing of this thin belt end portion.
Also, in this conventional belt fastening tool, the belt clamping bar is tightened against the belt by rotating a pair of screw handles that are screwed into the lower plate of the belt fastening tool; and sometimes the screw holes for the handles in the tool become filled with coal dust in a dirty coal mining operation and as such, is a source of maintenance problems and a hindrance to tool operation. Moreover, the clamping force obtained using the manual screw handles could be greater in order to achieve a better clamping of the belt to the tool. In addition to low clamping force from the screw handles, the above-described clamping bar may deflect or bend vertically or horizontally, thereby lessening the force being applied to clamp the belt. Therefore, a need exists for an improved clamp bar construction. Finally, very long belt ends, e.g., several feet to five feet may be difficult to insert in the gap between the upper and lower plates prior to being clamped.